It started back in '08 or '09 when I stumbled across a guy from New Zealand who had made billet cams for the RC in an effort to overcome the HRC cams that were snapping during races on decel. I emailed him and didn't hear back; but was surprised when 6 months later he finally did, saying he was making another batch of cams. So I ordered some up. Actually getting the cams took forever, but they showed up here in the US in early 2011. I took the bike off the road that March with the hope of spending about a year taking the engine apart, modding it, and getting it running again. Well 4 years later I finally got it done. Here are the engine mods:

I didn't get the power I had hoped out of it, but I knew full well before I started the project that the RC motor doesn't respond too well to "typical" power mods that most other motors tend to. Here's the chart:

Anybody that knows anything about tuning doesn't give a damn about the posted numbers. It is the difference between the baseline and final and yours looks very VERY healthy above 7000rpm and very similar to what I have seen before. Good Job!

Typically I see a broader range of overall gains from the HC pistons alone if the compressions increase is over at least 12.2, but the cam profile may very well be affecting those curves more than the pistons.

Ldh- in that respect, I agree with you however does not 114 seem a bit low for a rc51? I don't know profess to know much at all about rc51s, but I was just looking at dyno #s in your site and saw a cammed rc (no mention of any other internal mods) made 137. Again not a rc pro but 13 rwhp over stock with basically a built motor doesn't sound right at all. I know you're a messiah to the rc, but I'd like to think I know internal combustion engines in general fairly well

We simply do not know the calibration of the dyno. For the sake of argument since it appears to register low it could have easily registered 102rwhp with his stock bike if his exhaust and tune took him up to 114 and then another 13hp from cams/pistons on top of that is pretty normal and very respectable. Or maybe I read it wrong and his 114hp was the stock bike not the bike with the Exhaust & Tune...

Using that same 13hp gain on a bike with Sato Exhausts that typically would put out around 128rwhp on our dyno he would end up with 141 hp which is again pretty normal from all the builds I have witnessed with cams and HC pistons.

Anybody that knows anything about tuning doesn't give a damn about the posted numbers. It is the difference between the baseline and final and yours looks very VERY healthy above 7000rpm and very similar to what I have seen before. Good Job!

Typically I see a broader range of overall gains from the HC pistons alone if the compressions increase is over at least 12.2, but the cam profile may very well be affecting those curves more than the pistons.

Very nice either way.

Yes, the chart shows the base run with Satos and PC3; the higher line is with the internal mods.

I had hoped for over 130 at the rear wheel, but as I stated above, I knew going into it that the RC engine does not respond well to the usual internal mods that tend to give big gains. The resident RC51 expert here in the Phoenix area is Mark Ladesma; he's a former racer (raced and built RC's with the full HRC kit) and actually works at a big dealership as their engine mod/dyno guy. Mark provided a lot of advice and help as I did all the work on the engine, minus the cam gear swap which he did. I also brought the bike to him to do the dyno break-in and run, and he was pleased with how it turned out. My goal was to see how much power I'd get, but still keep it very rideable on the street, without spending ridiculous sums of money (which is easy to do on any bike, but really easy to do with this one).

All in all, I had a lot of fun working on the bike and I'm happy with how it turned out.

Great job on the mods. Just for my interest sake; do you know what compression your running now? Also, what octane level are you now using?

As I understand it, the JE pistons mimic the same CR as the HRC's. If you want to get the full 12.5 CR out of them though, you have to also install the HRC valves which don't have a dished profile on the face. I'm still running the stock valves which are dished a little, so the CR I think is around 11.5 or so.

At first I ran the bike on 91, but on my last tank full I filled up with 89; no problems at all.

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